Nearly 233 years ago, the signers of the Declaration of Independence enshrined those "unalienable rights" as essential to Americans.

Yet our Founding Fathers of 1776 didn't speculate on what it takes for an individual to be happy, affirming only that the freedom to pursue it is vital. There are no certain guidelines for personal happiness, even after generations have spent lifetimes pursuing the Great American Dream.

On its June cover, the Atlantic magazine features the article "What Makes Us Happy: Friends Matter Cholesterol Doesn't. Lessons From An Amazing 72-Year Study." The story is by Joshua Wolf Shenk.

He reports on the Harvard Study of Adult Development, which began in 1937 by focusing on a group of healthy, seemingly well-adjusted male sophomores. It has followed their lives for more than 70 years.

Psychiatrist George Vaillant, who became the project's chief curator, investigator and analyst, has been sifting through the findings for over four decades, seeking clues on happiness.

The study was conceived before World War II by Arlie Brock, a physician who was the director of Health Services at Harvard. He wanted to look into the question of what it takes to live well.

Over the years, more than 250 individuals -- about half of them still alive in their 80s -- have submitted regularly to numerous medical exams and psychological tests. They repeatedly have filled out questionnaires and responded to interviews. The subjects have mostly remained anonymous.

Their course has been studied in depth, from life at war during the 1940s, to marriages, to careers, to family life and finally to retirements.They were studied in sickness and in health.

Nearly a third of the men had by age 50 met the criteria for mental illness at one time or another during their lives under the microscope.

In fact, how people respond to life's inevitable trials and tribulations apparently plays a big role in who does and doesn't consider themselves happy.

What psychologists call adaptations, or defense mechanisms, are vital. Responses said to be immature are such things as acting out, fantasy, passive aggression and hypochondria.

More common in most people are so-called neurotic defenses, including repression of conflicts, disassociation and memory lapse. Among the better adaptations are humor, altruism, deferring responses to impulses and finding ways to channel feelings into healthy outlets.

"If we use defenses well," he says, "we are deemed mentally healthy, conscientious, funny, creative and altruistic. If we use them badly, the psychiatrist diagnoses us ill, our neighbors label us unpleasant, and society brands us immoral."

Negative emotions tend to insulate people immediately from their real problems; positive reactions to troubles can risk vulnerability and don't help so much right away as they do in the long run.

Tough guys do dance, or so it turns out.

Employing mature adaptations was found to be among several factors that predict healthy aging, both physically and psychologically. Other keys to happiness: Education, getting some exercise, maintaining a good weight and not smoking or abusing alcohol. Plus warm, stable relationships.

Health and happiness go hand in hand.

But Mr. Vaillant is said to have concluded that your cholesterol level at age 50 has nothing to do with being healthy in old age. An optimistic outlook is more to the point.

"Positive psychology" became something of a trend in the late 1990s, and systematic efforts to study the good life flourished everywhere from college campuses to popular society.

Believe it or not, money was found to do little to make us happier after our basic needs are met.

What does it take to be happy?

After years of study, Mr. Vaillant offers his conclusion: "That the only thing that really matters in life are your relationships to other people."